Introduction to Data Management

An Overview of Data Management
1-2 15873 Tandem Computers Incorporated
Figure 1-1. Online Processing and Database
S8020-001
NEW CUSTOMERS
JONES, JOE
ACME, INC.
105 S. MAIN
SAN JOSE, CA
CREDIT CHECK
JONES, JOE
ACME, INC.
105 S. MAIN
SAN JOSE, CA
Update
Credit
Inquiry
Database
In this environment, many users manipulate the database simultaneously and any
change made to the database by one user is visible to everyone else. For example, if a
customer deposits money at a bank, information about that deposit is instantly
available to all tellers at the bank.
The online environment allows the computer to process a transaction as soon as it is
entered at the terminal. The computer instantly locates the corresponding records in
the database, changes the necessary information on those records, and makes the
updated records available to anyone who wants to access them.
Screen-oriented processing allows users to view entire records in the database at a
single glance and to interact with the system through a simple interface. The users
can display and update individual records selectively, immediately correcting any
rejected entries.
To conduct online transaction processing with the most powerful and effective
techniques currently available, a computer system must offer two essential features:
Distributed storage of data, where different portions of the database reside on
different machines, perhaps even at different geographic locations
Relational database management, where users can access data in a convenient,
flexible, and efficient way
These principal features are described in the following pages.